SC Connecticut News

Yale scientists have identified two brain regions that control short- and long-term social gaze behavior, a discovery that could inform therapies for disorders like autism. The findings were published on May 31 in the journal Neuron.

"For primates, social gaze is an integral part of social interaction," said Steve Chang, an associate professor of psychology and neuroscience at Yale’s Faculty of Arts and Sciences and senior author of the study. "For example, monkeys want to see what others are looking at because there might be more resource opportunities. But eye contact that lasts a long time could also be a threatening gesture. So there’s this intricate balance of when to look at the eyes of another to get information but not send the wrong information."

In previous research, Chang and his colleagues identified brain regions in the prefrontal-amygdala networks where neural activity increased as monkeys gazed at each other. The new study aimed to determine how these regions influence social gazing behavior.

Researchers paired two rhesus macaque monkeys and used infrared cameras to track their eye positions. When one monkey looked at the other's eyes, it received real-time stimulation in one of three brain regions. The researchers then observed changes in the stimulated monkey's gaze.

They found that stimulation in the orbitofrontal cortex led to more concentrated spontaneous gazes around their partner's eyes for several seconds and reduced the time between gazes compared with monkeys that did not receive stimulation.

"Stimulation in this region also reduced the amount of time it took for a monkey to reciprocate another’s gaze," said Chang. "But none of these findings occurred when monkeys were in a non-social interaction, looking at a moving dot rather than another monkey’s eyes."

Stimulation within the dorsomedial prefrontal cortex had unique longer-term effects not seen in other regions. Over 1.5-hour sessions, this stimulation altered how gazes were exchanged between two monkeys.

"The gazes of partner monkeys were interacting over time in a kind of leader-follower pattern," said Chang. "Over the course of the stimulations, this relationship strengthened, but only with stimulations to the dorsomedial prefrontal cortex."

The findings highlight how these brain regions contribute to both momentary and long-term social gaze interactions. Understanding these contributions reveals potential intervention points for enhancing social behavior where it is diminished.

"We can envision a future therapeutic approach that builds on these findings using a social brain-computer interface," said Chang, "where we target these regions to enhance in-the-moment and long-term social attention."